Fuel injection pump

ABSTRACT

A plunger type fuel injection pump for use in a spark ignition internal combustion engine is disclosed. Fuel is pumped by displacement of the plungers with the timing and quantity of fuel delivered to the engine being determined by the sealing of a spill port by an appropriately shaped, axially and rotatably displaceable, land which is contoured to seal the spill passage when fuel delivery to the engine is desired. In order to match fuel flow characteristics with engine air flow characteristics throughout the entire speed and load range of the engine, and in particular over the part load operating range of the engine, plunger displacement is controlled by a contoured face cam in place of the normally provided swash plate. The cam contour is arranged to provide for a rate of plunger displacement which is increasing for a major portion of the 180* angular pump shaft rotation preceding the plunger top dead center position. The cam surface is radial with respect to its axis of rotation and the plungers are provided with means to engage the cam surface along a radial line and with means to prevent the plungers from rotating about their own axes.

United States Patent 1191 Simko Dec. 24, 1974 FUEL INJECTION PUMP Primary Examiner-William L. Freeh [75] Inventor: Aladar O. Simko, Dearborn Heights, Ass'stmt Examiner-Gregory Paul Lapomie Mich. Attorney, Agent, or F1rmRobert A. Benzlger; Keith L. Zerschling [73] Ass1gnee: Ford Motor Company, Dearborn,

Mlch- [57 ABSTRACT [22] Filed: Dec. 26, 1972 A plunger type fuel injection pump for use in a spark ignition internal combustion engine is disclosed. Fuel [21] Appl' 318297 is pumped by displacement of the plungers with the timing and quantity of fuel delivered to the engine [52] US. Cl 417/270, 123/139 AA, 417/294 being determined by the sealing of a spill port by an [51] Int. Cl. F04!) 49/00 appropriately shaped, axially and rotatably displace- [58] Field of Search 91/499; 92/129; 74/60; able, land which is contoured to seal the spill passage 417/270, 269, 293, 294 when fuel delivery to the engine is desired. In order to match fuel flow characteristics with engine air flow [56] References Cited characteristics throughout the entire speed and load UNITED STATES PATENTS range of the engine, and in particular over the part 2,061 144 11/1936 Stoutz 91 /507 load .merating range of the engine plunge? displace 2 775210 12/1956 417/269 ment 1s controlled by a contoured face cam 1n place of 2:832:831 4/1959 Dannevig 91/498 the normally provided swash plate. The cam contour 2,992,619 7/1961 Nilges 91/499 is arranged to provide for a rate of plunger displace- 3,045,604 7/1962 Hahn 74/60 ment which is increasing for a major portion of the 3,046,950 7/1962 Smith 91/491 180 angular pump shaft rotation preceding the 3,319,568 RCpkO 6t 31. plunger top dead enter position The cam surface is FOREIGN PATENTS OR APPLICATIONS radial with respect to its axis of rotation and the l 914 598 8/1970 German 91/499 plungers are provided with means to engage the cam y surface along a radial line and with means to prevent the plungers from rotating about their own axes.

7 Claims. 16 Drawing Figures 2 /27 22 9/ f 32 1;: 11 a m /z; ya I W Q /zz 5Z3 I 2 62 #4 k m:

PATENTEI] DEC 2 41976 SHEET 1 UF 5 FlG.2

FUENTED [H2 4 I974 SHEET 2 BF 5 FIG.3

FIG. 4

, IDLE SPRING STOP 1000 RPM I IDLE CONTROL 575 RPM CURB'STOP POS. 0-400 RPM PRIME I START FUEL INJECTION PUMP BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is related to the field of piston, or plunger type, fuel injection pumps for internal combustion engines operating on the Otto cycle. More particularly, the present invention is related to that portion of the above noted field in which a single actuator reciprocates a plurality of plungers. Specifically, the pres ent invention is related to that portion of the above noted field concerned with fuel injection pumps for constant air/fuel ratio operation of the associated engme.

DESCRIPTION OF THE PRIOR ART Plunger type fuel injection pumps for internal combustion engines are well known in the art. Single actuator plunger type fuel injection pumps are one well known form. One example is illustrated in US. Letters Pat. No. 3,319,568 assigned to the assignee hereof and titled Fuel Injection Pump Assembly.

As illustrated therein, such pumps provide a plurality of piston actuated pumping means arranged around a central bore and communicating with the central bore through a plurality of spill ports. Each pumping means communicates with a combustion chamber of an internal combustion engine. The central bore communicates with a source of fuel at a slight positive pressure. The plurality of plungers are arranged to be reciprocated through the rotary motion of a swash plate actuator mechanism and the quantity of fuel to be delivered to the engine is determined by the duration of closure of the spill port through the rotary actuation of a land mechanism which is received within the central bore. Timing of fuel delivery is also determined by the shape of the land. The land is rotated in synchronism with engine operation. Means are provided for altering the axial position of the rotary land within the central bore or passage and means are also provided for adjusting the rotational phasing of the land relative to rotation of the plunger actuating mechanism to achieve control of the duration and of the timing of spill port closure. The shape of the rotary land and hence the fuel delivery characteristic of the pump is determined with respect to the fuel requirements of the engine.

The prior art pumps of this type have been applied to engines having unthrottled air supplies. Such engines operate with an air/fuel ratio slightly richer in fuel than the stoichiometric ratio at maximum power operation (where the air intake manifold becomes flow limiting even in the absence of an air throttle) and part throttle operation results in a lean air/fuel ratio indicative of excess air. Such part load, lean operation provides for high efficiency but increases engine exhaust emissions, particularly the hydrocarbons and the oxides of nitrogen, so it has become desirable to provide an air throttle for such engines to maintain a constant air/fuel ratio over all operating ranges. FIG. 5 illustrates a typical set of air consumption curves, and hence fuel requirement curves, for an internal combustion engine having a throttled air inlet wherein the air consumption in pounds per cycle is graphed as a function of engine speed for three power levels of operation. The upper curve corresponds to maximum power, or wide open throttle operation, while the two lower curves correspond to an intermediate and a low power range of operation both of which may be termed part throttle operation. FIG. 6 illustrates fuel delivery curves of a prior art pump operated in conjunction with an engine having a throttled air inlet and corresponding to the air consumption curves of FIG. 5. While the wide open throttle curves are closely matched indicating constant air/fuel ratio and hence optimum power and combustion conditions, the part throttle curves illustrate that fuel delivery increases with respect to r.p.m., and the increase is more pronounced at the lighter load operation than at the intermediate loading level. This increase in fuel delivery as a function of load for increasing speed at part throttle settings is a result of the fact that the swash plate mechanism causes the linear velocity of the pumping plunger to be a maximum at before top dead center (TDC) and to be gradually decreasing from that point to TDC. The injection advance requires, at part throttle settings, that injection occur at high r.p.m. in proximity to 90 before TDC and at lesser degrees of advance (closer to TDC) as the speed of the engine decreases. Thus, the linear velocity of the pumping plunger is greater during the delivery portion of the stroke at large degrees of advance (higher engine speeds) causing an increase in the length of the delivery portion of the plunger stroke and increased pumping efficiency at higher speeds both of which result in increased fuel delivery with increased engine speed.

It is an object of the present invention to provide an improved fuel injection pump which provides a fuel delivery characteristic closely matching the engine air flow characteristic over all ranges of engine operation for an engine which may operate with a throttled air consumption and at wide open throttle. It is also an object of the present invention to provide a mechanism within a plunger type fuel injection pump for modulating the fuel delivery characteristic of the pump as a function of engine load so that the characteristic more closely matches the fuel requirement of the associated engine over all engine speed and load ranges. It is a further object of the present invention to provide such a mechanism in a form which does not greatly increase the cost and complexity of plunger type fuel injection pumps.

A secondary factor which contributes to the fuel delivery characteristic increasing with speed results from the efficiency of the prior art pumps increasing with increases in engine speed. These efficiency increases are due to (1) dynamic injection effects at the beginning and ending of each injection stroke which become more significant as engine speed and hence plunger speed increases and (2) to plunger and metering sleeve leakage which decreases with increases in plunger speed. In particular, as the speed increases, the velocity of the pumping plunger increases causing pumping pressure to reach the check valve opening pressure more rapidly during the transient conditions of spill port closings and openings. Leakage around the pumping plunger is also reduced since the time period during which leakage occurs is reduced at higher speeds further improving pumping efficiency. It is therefore an object of the present invention to provide a plunger type fuel injection pump which has a substantially constant fuel delivery characteristic for part throttle operation with an associated throttled air internal combustion engine. It is also an object of the present invention to provide a fuel injection pump with plunger actuating mechanism which provides a plunger displacement curve having an increasing slope over the major portion of the angular distance from 180 before TDC to TDC. It is a more specific object of the present invention to provide a fuel injection pump with a plunger actuating mechanism that provides a plunger displacement curve having an increasing slope over a significant portion of the angular distance from 90 before TDC to TDC.

The axial and phase positioning of the spill port closing land structure, also known as the helix, is accomplished by the combination of a governor mechanism and an operator controlled positioning lever. While suitable linkage mechanism could be designed to sense and respond to various conditions of engine loading to modulate or otherwise override the normally provided linkage mechanism, such an approach would result in a marked increase in cost and complexity and would be subject to tolerance buildup errors and/or to a degree of insensitivity either of which would make such an approach unattractive. It is, therefore, an object of the present invention to provide a mechanism for modulating fuel delivery as a function of engine loading which does not require the addition of linkage mechanism ex ternal of the fuel pump. It is a further object of the present invention to provide a mechanism for modulating fuel delivery in response to various degrees of engine loading and wide open throttle operation which is wholly contained within the fuel injection pump.

The single actuator plunger type fuel injection pumps according to the prior art have utilized a swash plate mechanism as the plunger actuator. A swash plate may be visualized as a cylinder having an actuator surface defined by the intersection of a plane with the axis of the cylinder at an angle other than a right angle. The particular angle of intersection is determined by the radius of the cylinder and the desired total plunger displacement. This actuator surface results in a need for fairly complex associated structure to mate with the actuator end or foot of the plunger, as for example, a ball and socket arrangement, or in the alternative, that the actuator ends of the plungers and the actuator surface must be provided with a suitable wear resistive material or must be manufactured using a surface hardening process to prevent the point contact between plunger and actuator surface from cutting a groove in the surface or otherwise abraiding the actuator surface and the actuator end or foot of the plunger. This is of course, a result of the constantly changing actuator surface angle with respect to the foot of any one of the plungers. It is, therefore, a further object of the present invention to provide an actuator surface which maintains a constant angular relationship with respect to the actuator end of the plungers so that the complicated actuator surface plunger interface mechanism can be eliminated and the plungers can be provided with means forming at least line contact with the actuator surface. The invention described in prior U.S. Letters Pat. No. 3,696,798, Combustion Process for Engine of Spark Ignition, Fuel Injection Type assigned to the assignee hereof, and of which I am a co-inventor, represents one attempted solution to the problem described above while the present invention represents an improved solution to this problem.

SUMMARY OF THE PRESENT INVENTION The present invention provides for a suitably contoured face cam in place of the normally provided swash plate mechanism to tailor the distance and rate of plunger displacement to more closely match the fuel delivery characteristics of the pump with fuel requirements of the engine. A plunger driving face cam according to the present invention is provided with a contour which actuates the plungers to provide for a gradually increasing rate of plunger displacement over a major angular segment of the portion of the face cam preceding top dead center (TDC). The velocity characteristics of the cam are sinusoidal at the beginning and ending of plunger lift but are flat with a gradual increase in velocity in the operating range. This permits the pump designer to provide plunger displacement as a controlled variable, along with land shape, to determine fuel delivery timing and quantity of fuel pumped.

In order to provide a constant angular relationship between the actuator surface and the feet of the plungers, the cam surface is arranged to be radial to the axis of rotation of the cam. That is, any straight line drawn from the cam surface to the axis of rotation of the cam will intersect the axis of rotation at a right angle. Each plunger is provided with a cylindrical foot, with the axis of the cylinder intersecting the axis of rotation of the cam at a right angle (and therefore parallel to the actuating surface of the face cam) to provide for line contact between the cam surface and the plunger foot. Means in the form of a shaped opening having a flat portion cooperating with a flat surface provided therefor on the plunger side is provided to keep the plunger foot axis in proper alignment particularly at TDC and 180 behind TDC.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of a fluid or fuel injection pump with which the present invention is of utility.

FIG. 2 is an enlarged cross sectional view of the pump assembly according to FIG. 1 utilizing the present invention.

FIG. 3 is a schematic representation of the fluid or fuel injection pump assembly shown in FIG. 2 illustrating the timing and duration control mechanism.

FIG. 4 is a representation of the fluid metering land employed by the fluid or fuel injection pump of FIG. 2.

FIG. 5 shows a graph of air consumption by an internal combustion engine having a throttled air inlet as a function of engine speed with one curve representative of air consumption at full load operation and two curves representative of air consumption at part load operation.

FIG. 6 shows a graph of fuel delivery as a function of engine speed for prior art injection pump for the three levels of air consumption illustrated in FIG. 5.

FIG. 7 shows a graph of fuel delivery as a function of engine speed for a similar injection pump which incorporates the present invention for the three levels of engine air consumption illustrated in FIG. 5.

FIG. 8 shows a sectional view of a plunger actuating face cam of the present invention.

FIG. 9 shows a sectional view taken along lines 9-9 in FIG. 2, of a pumping plunger according to the present invention.

FIG. 10 shows a top elevational view of the antirotation plate of one aspect of the present invention.

FIG. 11 is a series of graphs illustrating the operation of the prior art pumps wherein FIG. 11a illustrates the spill port opening and closing positions as functions of engine speed at a selected light load level of operation and FIG. 11b illustrates the plunger displacement and rate of displacement curves for a typical prior art swash plate actuating mechanism.

FIG. 12 is a series of graphs illustrating the operation of the fuel injection pump incorporating the actuating mechanism of the present invention wherein FIG. 12b illustrates the plunger displacement and rate of displacement curves for the actuating mechanism of the present invention and FIG. 12a is identical to FIG. lla.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in which like reference numerals designate like parts throughout the several views thereof, there is shown in FIG. 1 an external view of the fluid or fuel injection pump assembly according to the present invention which includes a housing enclosing the actuating mechanism and pump plunger for the plunger type fuel injection pump of the present invention. This housing 10 has a number of fuel discharge outlets 11 that are each adapted to be connected by an external hose to an individual fuel injec' tion nozzle, not shown.

The housing 10 includes a window 12 for observing the degree of injection advance; that is, for observing the timing of the pump to the engine, which will be described in more detail hereinbelow. .It also includes a window 14 adjacent an internal fuel reservoir to observe for air bubbles, etc., in the fuel for fuel vapor evaluation purposes. An externally controlled linkage 16 forms a portion of the engine control linkage mechanism, and partially controls the discharge of fuel through outlets 11 in a manner to be described. More specifically, as shown in FIG. 2, pump housing 10 has several sections bolted or otherwise secured together. These include a cover portion 20, a hollow upper housing portion 22 containing a flyweight governor mechanism, a central housing portion 26 containing the fuel pump plungers and fuel flow metering sleeve valve, and a lower housing portion 28 enclosing the drive shaft and the pump drive plate assembly according to the present invention.

Lower housing portion 28 has a central bore 30 in which is rotatably mounted a tubular drive shaft 32 on side bearings 33. The drive for this shaft is not shown, but it would, in general be driven by a geared take-off from the engine cam 0r crank shaft. The upper part of shaft 32 is formed integral with the drive plate or face cam 34 of the present invention, having a contoured drive surface 36 to be described in greater detail hereinbelow. Face cam 34 is rotatably mounted on thrust bearings 40.

A reciprocating-type piston or plunger 50 is axially movable in each of a plurality of bores or barrels 52 and the lower end 53 of each of these pistons or plungers 50 bears on the contoured drive surface 36 of face cam 34. Anti-rotation plate 54 cooperates with flats 51 provided on pistons or plungers 50 to prevent rotation of the plungers about their own axes, particularly at the top and bottom dead center positions ofeach plunger. This will be described in greater detail hereinbelow with reference to FIGS. 9 and 10. The upper end of each bore or barrel 52 is intersected by cross bores 56 and 58 in housing portion 26, the number of bores or barrels 52 corresponding to the number of cylinders or combustion chambers in the engine to which the fuel pump is to be connected. Bores 56 constitute discharge passages for fuel leading to delivery valves 59. Passages 58 constitute spill holes or ports connected to a central bore or fluid chamber 60 in housing section 26.

A fuel storage area 61 is provided on one side of pump housing portion 22, and is connected to chamber 60 by intersecting passages 62 and 64. An external fuel transfer pump (not shown) would be connected to passage 64.

In general, the upper end of each plunger 50 is fed with fuel from the chamber 60 through its associated spill holes 58 during the suction stroke or downstroke of the plunger. During the plunger discharge stroke or upstroke, fuel is displaced either back into chamber 60 or through the delivery valve 59. Fuel under pressure on the upper end of each plunger 50 forces the lower end 53 of each of these plungers or pistons into engagement with the contoured drive surface 36 of face cam 34.

With reference to FIGS. 2 and 3, fuel delivery from the pump is controlled primarily by proper phasing of a sleeve valve 70, having a metering helix 72, with respect to plunger displacement. The sleeve valve is capable of executing both axial and rotational movements to variably position metering helix 72 to close or open spill ports 58. This sleeve valve 70 is of the spool type, and has upper and lower lands 73 and 74 connected by a necked portion 76 of reduced diameter. The land diameters are such as to effectively seal the annular internal fuel reservoir defined between the lands while the diameter of the metering helix 72 is effective to seal spill ports 58 so that axial and rotary movement of the sleeve valve 70 will control fuel flow into chamber 60 from passage 62 and also the passage of fuel into and out of spill ports 58. Metering helix 72 may be formed as a raised circumferentially extending portion of the lower land 74 in the shape of a helix that is integral with the valve 70 and moves axially and rotatably with it, in a manner to be described, to progressively close or open spill ports 58.

The metering sleeve valve 70 surrounds an extension 82 of drive shaft 32, and can be moved both axially and rotatably with respect to it in the following manner. A tubular pump timing bushing is bolted to drive shaft 32 which is internally splined to the lower end of shaft 82. The two shafts are further connected by a pin 84 that is fixed to bushing 80 and projects through a slot 86 in shaft 82 to permit relative axial movement between them. Shaft 82 projects through an oil seal 87 and a thrust bearing 88, the thrust bearing being located axially in one direction by a retaining ring 90. Shaft 82 continues upwardly freely through metering valve 70, through a governor assembly 91, and into cover portion 20 through a journal bearing 92. The bearing 92 is inserted in an aperture in a partition 93 in housing portion 22. The upper end of shaft 82 has a slotted pivotal connection at 94 to a lever 95 that is fixed to a rotatably mounted rod 96 forming a part of the vehicle control linkage.

Thrust bearing 88 and metering valve 70 are axially separated by control spring 97 which surrounds shaft 82. The spring is seated at one end in a recess 98 in valve land 74 and at the other end against thrust bearing 88. The spring exerts a predetermined upward preload on metering valve 70. The upper end of valve 70 is also recessed, and is slidably (see FIG. 3) splined to a reduced diameter sleeve member 100. The sleeve member is fixed to the lower race 102 of a thrust bearing 104 that slidably surrounds shaft 82.

Sleeve member 100 has a cam follower slot 106 in which slides a drive pin 108 that is fixed to shaft 82. Slot 106 has an axially extending portion 110 and an inclined portion 1 12. Axial portion 110 permits relative axial movement between metering valve 70 and shaft 82, while inclined portion 112 forces the metering valve 70 to rotate to shaft 82 when the valve is moved axially. A second compression spring 114 surrounds shaft 82, and is seated between the lower end of sleeve member 100 and the bottom of recess 115 in upper land 73.

The thrust bearing 104, sleeve member 100, and valve 70 are moved axially downwardly by the mechanical flyweight governor assembly 91. This latter mechanism includes a cage or base plate 118 nonrotatably keyed to shaft 82. The cage has pairs of laterally spaced arms or ears 120, between which are pivotally mounted a pair of right-angled speed responsive members 122. The lower portion of each member 122 is formed as a weight 124, while the upper portion constitutes a lever 125 that abuts the upper race of bearing 104. Suitable screw adjusting devices 126 (in FIG. 2) provide adjustment in a known manner. The governor operates to depress sleeve valve 70 downwardly relative to shaft 82 against the forces of springs 97 and 114 upon outward movement of weights 124 under the effect of centrifugal force, in a manner further explained hereinbelow.

The preload of spring 114 maintains sleeve member 100 and metering valve 70 in their axially most separated positions shown in FIGS. 2 and 3 below a predetermined speed of rotation of shaft 82 of, say for example, 2,400 rpm; that is, below the speed at which injection advance is desired, as will be explained more fully hereinbelow. Above the speed at which injection advance is desired, centrifugal force acting on the governor weights 124 overcomes the preload of spring 114, and permits movement of sleeve 100 into the end of valve land 73.

Lubrication of the various parts is as follows: The accelerator control linkage and governor mechanism, as well as the upper portion of metering valve 70, are Iubricated by fuel sprayed into the upper housing portion chamber by means of a nonreturn lubricating jet assembly indicated at 127. The pump drive plate thrust and side bearings 40 and 33, and plungers 50, are lubricated by engine oil supplied through suitable intersecting passages 127' leading to these parts.

The accelerator pedal control linkage is illustrated schematically in FIG. 3. It includes an accelerator pedal 128 pivotally mounted at 129 and pivotally connected near its center to an articulated linkage consisting of links 130 and 131. These links 130 and 131 are pivotally connected to each other, with the opposite end of link 131 being fixed to the throttle valve 132 to control the quantity of air flowing into the intake manifold 133. Conduit 134 communicates the pressure within intake manifold 133 to a vacuum motor 135. Movable wall or diaphragm 136 is connected to linkage member 137 which is pivotally connected to linkage member 138. The other end of linkage member 138 is fixed to rod 96. Suitable wide open throttle and idle stops 139a and 139 are provided, as shown. A return spring 140 normally biases the pedal 128 to its idle position.

To prevent after running of the engine when the ignition is shut off, and to prevent overspeeding when desired, an additional external fuel shut-off linkage is provided. This consists of a power or manually movable knob 141 securedby a horizontally movable link 142.

to a fuel shut-off lever 143. The lever, in its simplest form, is fixed for rotation with rod 96 as shown in FIG. 3, and rotates between fuel shut-off and wide-open throttle positions, as indicated. The fuel shut-off position would move the metering helix 72 downwardly to a position completely opening spill ports 58 so that no fuel would be discharged through passages 56.

FIG. 2 shows the parts of the fluid or fuel injection pump assembly of the present invention described thus far in the curb stop or nonrunning position. The idle speed and injection advance springs 97 and 114 preload metering valve 70, sleeve member 100, and the governor members 122 to the positions shown. The manifold vacuum is maximized and diaphragm 136 is at its rightward (relative to FIG. 3) extreme position; therefore, no upward force is exerted on shaft 82 by this linkage. The metering helix 72 is positioned relative to the spill holes 58 at the point indicated in FIG. 4 as the curb stop position so that slightly more than the normal amount of fuel required to provide idle operation of the engine would be injected past the delivery valves if the fuel pump were to be driven at this time. Consequently, the auxiliary fuel control shut-off knob 141 (FIg. 3) would be moved to the left to move shaft 82 and valve downwardly to a fuel shut off position locating the spill holes 58 relative to helix 72 so that all of the fuel will spill back into chamber 60. This would correspond to the upper point 78 of the helix 72 being axially below the spill ports 58.

To start the engine, an amount of fuel far greater than the normal fuel load dispersion is desirable. The accelerator pedal 128 is depressed fully to its wide open throttle position, which also corresponds to the prime-start position. This full depression of the pedal causes lever to rotate clockwise to move shaft 82, governor mechanism 91, and metering valve 70 upwardly so that the bottom portion of the metering helix 72 now closes off spill holes 58 for almost the entire rotation of the metering valve as indicated in FIG. 4 as the prime start position. Once the engine is cranked, therefore, substantially the entire output from the pump plunger bores 52 will be forced into discharge passages 56.

As soon as the engine is started, the operator releases the accelerator pedal 128 to its idle or rest position. This again returns shaft 82 downwardly towards its original curb stop position, which schedules fuel discharge at a volume that will be greater than that needed to provide a selected engine idle speed of, say, 575 rpm. Simultaneously, however, the rotation of governor 91 at shaft speed now moves metering valve 70 further downwardly, and relative to shaft 82, against the force of spring 97 toward the idle speed position indicated in FIG. 4 as idle control. The preload of spring 97 is chosen such that below a predetermined lower idle limit r.p.m., such as 400 r.p.m., for example, it will prevent the governor from moving. Between the idle speed limits of, say 400-900 r.p.m., for example, the

opposing forces provided by spring 97 and the downward movement of metering valve 70, due to centrifugal force acting on the governor 91, will cause the metering valve 70 to reciprocate back and forth until it reaches an equilibrium position at the idle speed location chosen. V I

If the accelerator pedal is now again depressed, shaft 82 is raised, metering helix 72 now covers more of the area of spill holes 58, and the shaft speed increases. When the shaft speed reaches the upper idle speed limit of 900 r.p.m., the metering helix 72 will have been moved downwardly by the governor enough for the lower land 74 to contact a stop 99 on thrust bearing 88. This now renders the governor 91 inoperative above 900 rpm. to prevent any further movement downward relative movement of sleeve 70 with respect to drive shaft 82 so long as the preload of spring 114 remains in effect. As stated previously, this preload is operative to maintain land 73 and sleeve 100 in the relative positions shown below a speed of 2,400 rpm.

At 900 r.p.m., drive pin 108 will be positioned in the slot 106 of sleeve 100 at the junction between portions 110 and 112. Further change in the axial position of metering helix 78 between 900 and 2,400 rpm. is now,

therefore, controlled entirely as a function of the movements of accelerator pedal 128. That is, depression of the pedal will increase manifold pressure and the associated linkage will rotate lever 95 clockwise to raise shaft 82, governor mechanism 91, and sleeve valve 70 proportionally. Load control is now a direct function of accelerator pedal position.

Above 2,400 rpm, centrifugal force acting on governor weights 124 now is sufficient to overcome the preload of spring 114 and begin moving sleeve 100 into the upper end of sleeve valve 70, and downwardly relative to drive shaft 82. Since pin 108 must follow the curve of slot portion 1 12, the sleeve valve now is forced to rotate as well as move axially. This provides a change in the injection timing; that is, the helix 72 advances or rotates ahead relative to shaft 82 so that the fuel is now injected earlier. At a given speed of, say, 3,400 rpm, pin 108 will have moved to the end of inclined slot portion 112, and further axial and circumferential movement of the sleeve valve relative to shaft 82 will terminate.

Deceleration control is obtained by releasing the accelerator pedal to its idle position. Shaft 82, the governor assembly 91, and helix 72 immediately move downwardly, and decrease the fuel output. Since the governor is operative, the high centrifugal force still acting on the governor weights at first maintains spring 114 compressed, and the sleeve 100 almost entirely within land 72. However, as the speed decreases, the force of spring 114 will move valve 70 downwardly, so that at 2,400 rpm, spring 114 will have moved valve 70 to its downwardmost position relative to shaft 82, and valve 70 will be in its downwardmost position against stop 99. The helix 72 will now completely uncover the area of spill holes 58, and thereby shut off all fuel flow to the nozzles. When the speed falls within the 400-900 r.p.m. idle speed range, spring 97 and the governor will again be operative to move the sleeve valve 70 and metering helix 72 to the idle speed position.

Referring now to FIGS. 5 and 6, a series of graphs illustrating air and fuel consumption for a typical internal combustion engine are shown. FIG. 5 illustrates the air consumption in pounds per cycle graphed as a func- 204 illustrates the air consumption at a maximum power operation or wide open throttle setting and it can be seen by inspection of this curve that at wide open throttle, the air consumption does change as a function of engine speed with a significant decrease in the rate of consumption in the high rpm. range.

With particular reference now to FIG. 6, the fuel delivery in pounds per cycle for a fuel injection pump according to the prior art is illustrated. FIG. 6 illustrates fuel delivery at three operational loadings or throttle settings which correspond to those illustrated in the FIG. 5 graph. The curves 206 and 208 demonstrate a fuel delivery characteristic which increases with increasing r.p.m., while the curve 210 illustrates a fuel delivery characteristic which very closely matches the air consumption characteristic curve 204 from the graph of FIG. 5. In the prior art pumps, the configuration of the metering land or helix and its axial and rotary phasing were arranged to provide for a close fit between the fuel delivery characteristic and the air consumption characteristics at wide open throttle settings. This necessarily results in the pumping characteristic being excessive at operational loadings less than maximum or at part throttle operation. 1

Referring'now to FIG. 11, and in particular to FIG. 11a, a series of graphs are shown illustrating by the solid lines, the angular position of the metering helix 72, and consequently the opening and closing events and duration of closure of the spill port 58, relative to plunger top dead center for a representative pumping means as a function of engine speed for a selected light load, or part throttle, operation for a fuel injection pump associated with a representative internal combustion engine having a throttled air inlet. Angular position is expressed in degrees before pumping plunger TDC. It can be seen from the FIG. 11a graph that at the selected illustrative part throttle operation, the spill port 58 will be closed by metering land or helix 72 for approximately 30 of pump shaft angular rotation commencing about before plunger TDC and ending about 40 before plunger TDC at low engine speeds and that the injection time period will advance by approximately 22 /2 of pump shaft angular rotation for high speed operation. Since the normal practice is to have the pump shaft directly coupled or geared to the engine crankshaft, the degree of angular rotation for the engine crankshaft and for the pump shaft and for the actuating means of the pump will be approximately identical. FIG. 11a also illustrates by dashed lines, the spill port closing and opening events and duration of spill port closure at a high load or wide open throttle operation over the expected range of engine speeds. From a consideration of FIG. 11a, it can be seen that the total potential spill port closure is approximately 107 of angular rotation extending from about 146 before plunger TDC to about 40 before plunger TDC for this particular engine and prior art pump -combination. It can be seen from a consideration of FIG. 11a that the injection duration and injection advance can be directly controlled by the axial and rotary positioning of the metering land or helix 72 relative to spill port 58 by the mechanism described with reference to FIGS. 2 and 3 to suit the engine fuel delivery requirements.

With particular reference now to FIG. 11b, the plunger displacement and rate of displacement curves are graphed as a function of the angular positioning of a typical prior art swash plate type actuating mechanism. In order to illustrate one of the major difficulties with this prior art type of actuating mechanism, the angular positioning of the swash plate has been illustrated in alignment with the angular positioning for the spill port closing and opening events. Assuming for the purposes of illustration that the dynamic pumping effects associated with the differences in plunger velocity are minimal or zero, that is, that the opening and closing events are instantaneous and leakage is constant or zero, one can graphically analyze the quantity of fuel delivered tothe engine by considering the pumping mechanism as a positive displacement pump which will pump fuel to the engine only during the period of spill port closure. Under such conditions and assumptions, the quantity of fuel pumped will be directly proportional to the distance of plunger displacement during spill port closure. The FIG. 11b graph illustrates a plunger displacement of approximately 5.4 units of distance for the low speed spill port closure (which occurs without any additional amount of injection advance) as compared with a plunger displacement of approximately 6.7 units of distance for the high speed spill port closure event (which occurs at a maximum condition of injection advance). The reason for this increase in plunger displacement and its concomitant significant increase in the quantity of fuel delivered to the engine can most readily be appreciated from a consideration of the plunger velocity, or rate of displacement curve. As illustrated in FIG. 11b, the rate of displacement curve is one-half of a sinusoidal wave which reaches a maximum value at a point 90 before plunger TDC and thereafter decreases to a value of zero at plunger TDC. Thus, the plunger is moving with a relatively higher velocity at the position of maximum injection advance (at the illustrated part throttle operation) and is moving with a much lower relative velocity at the minimum degree of injection advance. Thus, considering spill port closure to be constant in terms of degrees of angular rotation over the entire speed range of the pump, it is thus readily apparent that the plunger velocity and therefore the distance of plunger displacement is greatly different for different amount of injection advance. This difference can also be seen to contribute to increases in fuel pumped for increasing engine speed under constant load operation of the associated engine over the speed range of operation of that engine.

The plunger displacement curve of FIG. 11b will be recognized as constituting the profile curve of the actuating mechanism applied to the plunger, expressed in terms of axial height from a zero reference for degrees of rotation before plunger TDC with the maximum displacement corresponding to the plunger TDC and identified as zero degrees. This curve is recognized as being one half of a sinusoidal wave going from a minimum value at 180 of rotation before plunger TDC and going to a maximum value at plunger TDC. This curve is the displacement curve generated by a typical swash plate actuating mechanism as defined hereinabove.

Referring now to FIGS. 8 and 12, the actuating mechanism of the present invention will be described and is illustrated. With particular reference to FIG. 8,

it can be seen that the actuating mechanism 34 of the present invention is provided with an actuating surface 36 from which an imaginary line drawn to intersect the axis of rotation will intersect that axis at a predetermined, constant angle without regard to the location on the actuating surface from which the line is drawn. Preferably, this angle of intersection is a right angle so that the actuating surface may be termed to be radially directed with respect to the axis of rotation of the actuating mechanism 34. This actuating surface 36 constitutes a ramp surface for actuating the pumping plungers of the fuel injection pump. The circumferential profile of actuating surface 36 is arranged to provide a pumping contour in terms of linear displacement for varying degrees of angular rotation which differs significantly from that illustrated by the displacement curve of FIG. 11b. With reference to FIG. 12 wherein FIG. 12a is substantially identical with FIG. 11a and with particular reference to FIG. 12b it can be seen that the differences between the displacement curves of the prior art device and of the instant device superficially appear to be similar. However, a consideration of the velocity or rate of displacement curves quickly disspells any such thoughts of similarity.

The displacement curve of FIG. 126 has segments a, b and c all of which appear to be linear. Segments a and c are, in fact, short segments of larger sinusoidal curves whose importance is to provide a rapid initial acceleration and a rapid terminal deceleration for the plungers. Segment b of this curve is of cardinal importance. Segment b of the rate of displacement curve of FIG. 12b is provided with a slope which does not decrease in the region between before TDC and TDC but which increases over the range of angular rotation from about l47 /2 before plunger TDC, through 90 before TDC to about 42 /z before plunger TDC. This increasing slope, which in this instance is linear, assures that the plunger displacement curve, and hence plunger displacement, will not decrease for equal increments of angular rotation approaching TDC until the angular rotation has reached a point approximately 42% before plunger TDC. This assures that the difficulty encountered in the prior art at part throttle operation as a result of the displacement and rate of displacement curves, particularly as illustrated and described with reference to FIG. 11b, will not occur in the fuel pump incorporating the actuating mechanism of the present invention. By way of comparison, and using identical RPM evaluation points selected for this purpose in FIGS. 11a and 12a, it can be seen that the plunger displacement for a plunger actuated by the face cam of the present invention is approximately 6.0 units at the low r.p.m. speed and also approximately 6.0 units at the high rpm. range of operation. It can thus be seen that by incorporating the actuating mechanism of the present invention the deleterious effects of changing plunger velocity as a function of the changes in plunger speed encountered for different amounts of injection advance and resulting from the particular plunger velocity curve for prior art actuating mechanisms has been successfully avoided.

By further providing that the segment b of the velocity curve is increasing over its entire region of operation, the undesired efficiency improvement effects at high engine speeds as described hereinabove can be largely avoided or eliminated by providing a slight decrease in plunger velocity and hence slightly lower displacement at higher engine speeds. However, in the particular example cited, this is not apparent due to the fact that the plunger velocity curve reaches a maximum value slightly in advance of the opening of the spill port and termination of the spill port closure event and that thereafter the plunger is rapidly decelerated according to the profile of segment c. Thus in the example cited, for a slight amount of angular rotation, in this instance approximately 2% degrees, the plunger has been decelerated and hence executes somewhat less displacement motion and therefore pumps a slightly lesser quantity of fuel. In the particular situation illustrated, this is necessitated by the need to bring the plunger velocity down to zero in a very short amount of angular rotation in an efficient manner. However, for other engine applications where the overall quantities of fuel may differ greatly, the maximum point for the velocity curve can readily be made to fall outside of the pumping region or spill port closure regime for the particular fuel injection pump.

Again with particular reference to FIG. 8 and the displacement curve of FIG. 1217, it can be seen that plunger displacement curve of FIG. 12b corresponds to the circumferential profile curve of the actuating surface 36 expressed in terms of linear displacement in the axial direction from a reference for degrees of angular rotation of that actuating surface with respect to TDC. In order to obtain an actuating face cam 34 having the desired actuating surface profile, the actuating mechanism 34 may be radially ground on suitable radial grinding machinery which may be manually or automatically controlled to provide for the angular profile curve expressed as the displacement curve of FIG. 1212.

With particular reference to FIGS. 8, 9 and 10, a further aspect of the present invention is described. In order to simplify the manufacturing procedure for obtaining the actuating mechanism 34 of the present invention, and to provide for a simplification within the fuel injection pump incorporating the present invention, the actuating surface 36 is arranged to be radially directed, or perpendicular to the axis of rotation of the actuating mechanism 34. This permits the pump manufacturer to ignore any displacement or velocity changes in the plunger motion occasioned by changes in the angular relationship between the feet of the plungers and the actuating surface 36. To further aid in obtaining this result, the foot 53 of the plunger 50 according to FIG. 9 is arranged to be cylindrical with the axis of the cylinder being directed parallel to the actuating surface 36. For the actuating surface 36 is illustrated in FIG. 8, the axis of the cylinder is directed perpendicularly to the axis of rotation of the actuating mechanism 34 so that the foot of the plunger will be in line contact with the actuating surface 36 for all positions of angular rotation. Since the line contact will coincide with the axis of the plunger 50 at the TDC and at 180 before TDC positions, undesirable rotation of the plunger about its own axis may readily occur. A partial rotation of this plunger about its axis could readily result in a point contact occurring between an edge of the foot 53 of the plunger 50 and actuating surface 36. This point of contact would rapidly wear away or otherwise abraid both the plunger 50 and the actuating surface 36. To

holes 55 equal in number to the number of plungers 50 and each such hole 55 in this instance is provided with straight edged region 55'. These straight regions 55' are sized and positioned to cooperate with flats provided therefor on the sides of pumping plungers 50 to prevent any rotation of these plungers about their own axis.

It can therefore be seen that the instant invention readily accomplishes its stated objectives. By providing an actuating surface 36 for the actuating mechanism 34 which has a contour shaped to provide a desired displacement and velocity of displacement curve the pumping efficiency effect and the velocity change effect occasioned by prior art devices which made their fuel pumping characteristic different from the air consumption characteristic of their associated engine can be readily avoided. Furthermore, the particular contour applied to actuating surface 36 may be readily selected to conveniently match the air consumption characteristic of the associated engine. By also providing an actuating surface 36 which is perpendicular to the axis of rotation of the actuating mechanism 34 and by providing cylindrical feet for the pumping plungers 50 with the axis of these cylinders intersecting the axis of rotation of the actuating mechanism 34 the present invention simplifies the required structural elements of a fuel injection pump which may be used and also assures that the velocity and rate of plunger displacement will not be deleteriously affected by changing angular relationships between the actuating surface and the feet of the plunger 53. With reference to FIG. 7 it can be seen that the fuel injection pump according to the present invention provides fuel delivery at part throttle operation, illustrated by curves 212, 214 which closely matches air consumption as illustrated by curves 200, 202 of FIG. 5. The full load or wide open throttle fuel delivery curve 216 also closely matches the air consumption curve 204 of FIG. 5.

What I claim is:

l. A fuel injection pump for an air throttled internal combustion engine comprising in combination:

a housing;

fuel supply means communication with the housing;

means forming a plurality of fuel receiving bores within the housing and including fluid discharge communication means between said bores and said engine and further including a plurality of spill passage means for communicating the bores with the fuel supply means;

a plurality of plungers received within the bores in a one-to-one relationship therewith;

a metering valve means arranged to close the spill passage means in a selected sequence;

drive means adapted to be driven by the engine and including means for driving said metering valve to thereby sequentially close said spill passage means in the selected sequence and means for reciprocating said plungers within said bores; and

means responsive to the engine, operable to control the quantity of fuel pumped to the engine by said plungers;

said engine responsive means including speed responsive means within said housing operatively coupled to said metering valve and arranged to controllably vary the phase relationship between spill passage means closure events and engine operation whereby the spill passage means closure event may be advanced with increasing engine speed over selected ranges of engine operation;

said means for reciprocating the plungers including rotary drive means arranged to engage said plungers, operative upon rotation to reciprocate said plungers within said bores;

said rotary drive means including a contoured cam actuating surface for engagement with said plungers, the contour of said cam actuating surface being selected to provide plunger displacement velocities which do not decrease for drive means rotational positions corresponding to substantially all possible rotational positions of spill port closure by said metering valve means, whereby the cam actuating surface cooperates with the advance of the metering valve means and the concomitant advance of the spill passage means closure events to provide a fuel delivery characteristic which closely matches the air flow characteristic of the engine over substantially the entire speed range of the engine.

2. The fuel injection pump of claim 1 wherein said cam actuating surface is contoured to provide for an increasing velocity of plunger displacement for a major portion of the angular rotation of said rotary drive means prior to attainment of plunger top dead center within the plunger bore.

3. The fuel injection pump of claim 1 wherein the cam actuating surface is arranged to provide for a maximum velocity of plunger displacement at an angular position substantially corresponding to the angular position of the spill port closing event most closely approaching plunger top dead center.

4. The fuel injection pump of claim 3 wherein the cam actuating surface is arranged to provide for a velocity of plunger displacement which is increasing for substantially all of the cam means angular rotation corresponding to the total potential spill port closure.

5. The method of operating a fuel injection pumping apparatus for an air-throttled internal combustion engine, the pumping apparatus being of the type having a plurality of displaceable plunger pumping means in one-to-one relation, and in fluid communication, with the combustion chambers of the engine, a plurality of spill ports, a rotary spill port valve for sequentially closing selected ones of said spill ports whereby fuel is discharged from the pumping means having its spill port closed and means for communicating the discharged fuel to the associated combustion chamber, comprising the steps of:

driving said spill port valve in rotation about an axis in synchronism with engine operation;

displacing said spill port valve in an axial direction to vary the duration of closure of the spill ports in response to conditions of engine speed, engine load, and operator demand;

displacing said spill port valve in a rotational direction in response to selected conditions of engine speed and load to vary the phase relationship of fuel delivery with respect to engine operation; and

actuating said pumping means to provide a plunger displacement velocity which does not decrease during substantially the entire range of potential spill port closure duration, whereby the fuel pumping rate in pounds of fuel per cycle of engine operation may be maintained substantially proportional tled internal combustion engine comprising, in combi- 5 nation:

a stationary housing having a central bore and a source of fluid under pressure connected to said bore;

a rotatable drive shaft member mounted in said bore;

drive shaft driven fluid pumping means having a plurality of fluid discharge passages each connected in parallel to a fluid discharge injection line and to a fluid spill line communicating with said bore, said spill line receiving fluid from and spilling fluid into said bore;

a drive shaft driven fluid metering valve member slidably and rotatably mounted in said bore between said source and said spill lines;

means connecting said metering and drive shaft members for limited relative axial and rotational movements therebetween;

said metering member having fluid flow control portions thereon variably controlling the flow of fluid through said spill lines as a function of the axial and rotative movements of said metering member;

movable external control means;

means responsive to movement of said external control means in one direction for moving said drive shaft and metering members axially in a spill line closing direction; and

speed responsive governor means coaxially disposed about and driven by said drive shaft member for moving said metering member axially in an opposite, spill line opening, direction;

said limited movement connection between said metering and drive shaft members including a cam element and cam follower element operably engaged and connected respectively one element to each of the said metering and shaft members whereby rotation of said drive shaft member above a first predetermined speed effects a relative rotation between said members to vary the scheduling of control of said spill lines by said metering member;

said drive shaft driven fluid pumping means including a plurality of piston members arranged for reciprocation within a plurality of pumping cylinders and a rotary piston actuator having contoured drive surface, said drive surface having a fluid pumping segment for providing a piston displacement velocity which does not decrease for rotation of the drive surface through angular positions of rotation corresponding with substantially all possible scheduling of the control of the spill lines by said metering member whereby said fluid pumping segment and said limited motion connection may be made cooperative to provide a rate of fluid pumping substantially proportional to the rate of air consumption by the engine.

7. A fuel injection pump assembly for an air-throttled internal combustion engine comprising, in combination:

a centrally bored housing;

a source of fluid in fluid communication with said bore;

an axially movable rotatable drive shaft member extending through said bore;

drive shaft driven fluid pumping means arranged to be driven by the engine in relation to engine operational events and having a plurality of fluid spill lines connected at one end to discharge outlets and at their other ends to said bore to receive fluid from said source and to spill fluid into said bore;

a valve member slidably and rotatably mounted in said bore surrounding said drive shaft member and having a lost motion connection thereto;

said valve member having a fluid metering helix portion thereon variably closing said spill lines as a function of the axial and rotative movements of said valve member to control flow volume of fluid to said outlets;

movable external control means connected to said drive member for moving it and said valve member axially;

speed responsive governor means coaxially disposed about and driven by said drive shaft member for moving said valve member axially, said lost motion connection providing a relative rotation between said valve member and said drive member upon movement of said speed responsive means in a selected speed range to provide a variable control of the phasing of the closure event of said spill lines by said valve member with respect to engine operational events, whereby the discharge of fluid by the pump may be advanced in time with respect to engine operation;

said drive shaft driven fluid pumping means further including a plurality of pumping cylinders having plungers disposed therein and a rotary actuator driven in synchronism with said drive member;

said rotary actuator having an actuating surface arranged to reciprocate said plungers within their cylinders and contoured to provide a velocity of plunger displacement which does not decrease for substantially all possible spill port closure events whereby said fluid pumping segment and said limited motion connection may be made cooperative to provide a rate of fluid pumping substantially proportional to the rate of air consumption by the engine. 

1. A fuel injection pump for an air throttled internal combustion engine comprising in combination: a housing; fuel supply means communication with the housing; means forming a plurality of fuel receiving bores within the housing and including fluid discharge communication means between said bores and said engine and further including a plurality of spill passage means for communicating the bores with the fuel supply means; a plurality of plungers received within the bores in a one-toone relationship therewith; a metering valve means arranged to close the spill passage means in a selected sequence; drive means adapted to be driven by the engine and including means for driving said metering valve to thereby sequentially close said spill passage means in the selected sequence and means for reciprocating said plungers within said bores; and means responsive to the engine, operable to control the quantity of fuel pumped to the engine by said plungers; said engine responsive means including speed responsive means within said housing operatively coupled to said metering valve and arranged to controllably vary the phase relationship between spill passage means closure events and engine operation whereby the spill passage means closure event may be advanced with increasing engine speed over selected ranges of engine operation; said means for reciprocating the plungers including rotary drive means arranged to engage said plungers, operative upon rotation to reciprocate said plungers within said bores; said rotary drive means including a contoured cam actuating surface for engagement with said plungers, the contour of said cam actuating surface being selected to provide plunger displacement velocities which do not decrease for drive means rotational positions corresponding to substantially all possible rotational positions of spill port closure by said metering valve means, whereby the cam actuating surface cooperates with the advance of the metering valve means and the concomitant advance of the spill passage means closure events to provide a Fuel delivery characteristic which closely matches the air flow characteristic of the engine over substantially the entire speed range of the engine.
 2. The fuel injection pump of claim 1 wherein said cam actuating surface is contoured to provide for an increasing velocity of plunger displacement for a major portion of the angular rotation of said rotary drive means prior to attainment of plunger top dead center within the plunger bore.
 3. The fuel injection pump of claim 1 wherein the cam actuating surface is arranged to provide for a maximum velocity of plunger displacement at an angular position substantially corresponding to the angular position of the spill port closing event most closely approaching plunger top dead center.
 4. The fuel injection pump of claim 3 wherein the cam actuating surface is arranged to provide for a velocity of plunger displacement which is increasing for substantially all of the cam means angular rotation corresponding to the total potential spill port closure.
 5. The method of operating a fuel injection pumping apparatus for an air-throttled internal combustion engine, the pumping apparatus being of the type having a plurality of displaceable plunger pumping means in one-to-one relation, and in fluid communication, with the combustion chambers of the engine, a plurality of spill ports, a rotary spill port valve for sequentially closing selected ones of said spill ports whereby fuel is discharged from the pumping means having its spill port closed and means for communicating the discharged fuel to the associated combustion chamber, comprising the steps of: driving said spill port valve in rotation about an axis in synchronism with engine operation; displacing said spill port valve in an axial direction to vary the duration of closure of the spill ports in response to conditions of engine speed, engine load, and operator demand; displacing said spill port valve in a rotational direction in response to selected conditions of engine speed and load to vary the phase relationship of fuel delivery with respect to engine operation; and actuating said pumping means to provide a plunger displacement velocity which does not decrease during substantially the entire range of potential spill port closure duration, whereby the fuel pumping rate in pounds of fuel per cycle of engine operation may be maintained substantially proportional to the air consumption rate for all operational speeds of the engine.
 6. A fuel injection pump assembly, for an air throttled internal combustion engine comprising, in combination: a stationary housing having a central bore and a source of fluid under pressure connected to said bore; a rotatable drive shaft member mounted in said bore; drive shaft driven fluid pumping means having a plurality of fluid discharge passages each connected in parallel to a fluid discharge injection line and to a fluid spill line communicating with said bore, said spill line receiving fluid from and spilling fluid into said bore; a drive shaft driven fluid metering valve member slidably and rotatably mounted in said bore between said source and said spill lines; means connecting said metering and drive shaft members for limited relative axial and rotational movements therebetween; said metering member having fluid flow control portions thereon variably controlling the flow of fluid through said spill lines as a function of the axial and rotative movements of said metering member; movable external control means; means responsive to movement of said external control means in one direction for moving said drive shaft and metering members axially in a spill line closing direction; and speed responsive governor means coaxially disposed about and driven by said drive shaft member for moving said metering member axially in an opposite, spill line opening, direction; said limited movement connection between said metering and drive shaft members including a cam elemenT and cam follower element operably engaged and connected respectively one element to each of the said metering and shaft members whereby rotation of said drive shaft member above a first predetermined speed effects a relative rotation between said members to vary the scheduling of control of said spill lines by said metering member; said drive shaft driven fluid pumping means including a plurality of piston members arranged for reciprocation within a plurality of pumping cylinders and a rotary piston actuator having contoured drive surface, said drive surface having a fluid pumping segment for providing a piston displacement velocity which does not decrease for rotation of the drive surface through angular positions of rotation corresponding with substantially all possible scheduling of the control of the spill lines by said metering member whereby said fluid pumping segment and said limited motion connection may be made cooperative to provide a rate of fluid pumping substantially proportional to the rate of air consumption by the engine.
 7. A fuel injection pump assembly for an air-throttled internal combustion engine comprising, in combination: a centrally bored housing; a source of fluid in fluid communication with said bore; an axially movable rotatable drive shaft member extending through said bore; drive shaft driven fluid pumping means arranged to be driven by the engine in relation to engine operational events and having a plurality of fluid spill lines connected at one end to discharge outlets and at their other ends to said bore to receive fluid from said source and to spill fluid into said bore; a valve member slidably and rotatably mounted in said bore surrounding said drive shaft member and having a lost motion connection thereto; said valve member having a fluid metering helix portion thereon variably closing said spill lines as a function of the axial and rotative movements of said valve member to control flow volume of fluid to said outlets; movable external control means connected to said drive member for moving it and said valve member axially; speed responsive governor means coaxially disposed about and driven by said drive shaft member for moving said valve member axially, said lost motion connection providing a relative rotation between said valve member and said drive member upon movement of said speed responsive means in a selected speed range to provide a variable control of the phasing of the closure event of said spill lines by said valve member with respect to engine operational events, whereby the discharge of fluid by the pump may be advanced in time with respect to engine operation; said drive shaft driven fluid pumping means further including a plurality of pumping cylinders having plungers disposed therein and a rotary actuator driven in synchronism with said drive member; said rotary actuator having an actuating surface arranged to reciprocate said plungers within their cylinders and contoured to provide a velocity of plunger displacement which does not decrease for substantially all possible spill port closure events whereby said fluid pumping segment and said limited motion connection may be made cooperative to provide a rate of fluid pumping substantially proportional to the rate of air consumption by the engine. 